Color liquid crystal panel, method for manufacturing the same, and color liquid crystal display device employing the same

ABSTRACT

Within a reflective display section R, a part of a light that reaches a reflective electrode through a color filter exits to the outside through slits and a part of a light that reaches the reflective electrode through the slits exits to the outside through the color filter. In addition, a light reaching the reflective electrode through the color filter and exiting to the outside through the color filter, and a light having no opportunity to pass through the slits also can be observed. Therefore, a mean film thickness of color filter through which all lights pass during the time in which they travel the associated distance after they are inputted to the inside until they are outputted to the outside becomes nearly equal to that could be observed in the transmissive section T.

BACKGROUND OF THE INVENTION

1. Technical Field of the Invention

The present invention relates to a color liquid crystal panel suitablyused as a display of a portable telephone, a method for manufacturingthe same, and further a color liquid crystal display device employingthe same, more particularly, to a color liquid crystal panel having anenhanced capability of displaying high quality images, a method formanufacturing the same, and further a color liquid crystal displaydevice employing the same.

2. Description of the Related Art

It is conventionally known that a semi-transmissive liquid crystaldisplay device consisting of a plurality of pixels, each having atransmissive display section and a reflective display section therein,has been developed as a liquid crystal display device equipped with bothfeatures of a transmissive liquid crystal display device and areflective liquid crystal display device. In such a semi-transmissiveliquid crystal display device, a color filter for a transmissive displaysection and a color filter for a reflective display section are providedcorresponding to each color to be displayed and therefore, totally sixkinds of color filters are to be provided corresponding to each color.Accordingly, in order to manufacture a color liquid crystal displaydevice having the above-described construction of color filter, it isnecessary that six kinds of photoresist films are prepared correspondingto those color filters and then, six photolithography steps are carriedout. Consequently, there has been found a drawback in that thesemi-transmissive liquid crystal display device manufactured inaccordance with the above-described method results in a low yield andhigh manufacturing cost thereof.

In consideration of the above-stated drawback, the followingsemi-transmissive liquid crystal display device has recently beendisclosed in publications such as Japanese Patent Application Laid-openNo. 2000-111902. That is, a semi-transmissive liquid crystal displaydevice is constructed such that only one kind of color filter is formedcorresponding to each color and a region in which no color filter existsis formed within a reflective display section.

FIG. 1 is a plan view illustrating a layout of a TFT substrate includedin a conventional semi-transmissive liquid crystal display devicedisclosed in Japanese Patent Application Laid-open No. 2000-111902 andFIG. 2 is a cross sectional view of a liquid crystal panel employed inthe conventional semi-transmissive liquid crystal display device, takenalong the line A-A of FIG. 1.

In the conventional semi-transmissive liquid crystal display devicedisclosed in the publication, a red color pixel 101R, a green colorpixel 101G and a blue color pixel 101B are disposed in this order in adirection in which a scanning signal line extends. In each pixel, a thinfilm transistor (TFT) 102 is formed. The thin film transistor 102consists of a gate electrode 103 a projecting from a gate line 103 asthe scanning signal line and a drain electrode 104 a projecting from adrain line 104 that extends in a direction perpendicular to the gateline. The gate line 103 and the gate electrode 103 a are formed on atransparent substrate 100 a and further, an insulation film 105 isformed on the transparent substrate 100 a covering the gate line 103 andthe gate electrode 103 a. The drain line 104 is formed on the insulationfilm 105. An amorphous silicon layer 106 is formed on the insulationfilm 105 to face the gate electrode 103 a and the drain electrode 104 ais formed extending on the amorphous silicon layer 106. Furthermore, asource electrode 107 is formed extending from the amorphous siliconlayer 106 in a direction apart from the drain electrode 104 a while apart of the source electrode is at least positioned on and inside theamorphous silicon layer.

Within a reflective display section of each pixel, projecting portions108 are formed on the insulation film 105 and within a transmissivedisplay section, a transparent electrode 109 is formed on the insulationfilm 105. Note that the reflective display section is formed to surroundthe transmissive display section. Furthermore, within a region excludingthe transmissive display section in each pixel, an insulation film 110covering the projecting portions 108, the thin film transistor 102 andthe like is formed and further, a contact hole 111 is formed in theinsulation film 110 so as to reach the surface of the source electrode107. A reflective electrode 112 is formed within the contact hole 111and on the insulation film 105. The reflective electrode 112 has aconvex-concave surface reflecting the profile of the projecting portions108. The reflective electrode 112 is connected also to the transparentelectrode 109. Furthermore, a retardation film 113 and a polarizer 114are formed on the transparent substrate 100 a on a side thereof definedas the surface on which elements such as the thin film transistor 102are not formed. The elements constructed as described above constitute aTFT substrate.

Additionally, another transparent substrate 100 b is disposed inparallel with the transparent substrate 100 a on a side thereof definedas the surface on which the thin film transistor 102 is formed. A colorfilter (CF) 121 and an opposing electrode 122 are formed on a surface ofthe transparent substrate 100 b on a side thereof facing the transparentsubstrate 100 a. As shown in FIG. 1, the color filter 121 is formedextending in parallel with the drain line 104 and further, when viewinga pixel in a direction perpendicular to a surface of the associatedtransparent substrate, the transparent electrode 109 is being formedinside with respect to both end lines of the color filter 121 whereasthe reflective electrode 112 is being formed to have a width extendingbeyond the both lines thereof. Furthermore, a retardation film 123 and apolarizer 124 are formed on the transparent substrate 100 b on a sidethereof defined as the surface on which elements such as the colorfilter 121 are not formed. The elements constructed as described aboveconstitute a CF substrate.

In addition to the above-described construction of liquid crystal panel,a liquid crystal 130 is interposed between the TFT substrate and the CFsubstrate to constitute the liquid crystal panel.

The conventional color liquid crystal display device constructed asdescribed above has one kind of color filter therein corresponding toeach color and therefore, can be manufactured through a reduced numberof process steps, thereby improving a yield thereof.

Furthermore, as the color filter 121 of the CF substrate employed in theabove-described color liquid crystal display device has a regiontherein, facing the reflective electrode 112, in which the color filter121 is not formed, the color liquid crystal display device can offer adisplay brightness greater than that could be achieved in a color liquidcrystal display device developed before the emergence of color liquidcrystal display device employing such construction of the color filter121.

Moreover, the conventional reflective liquid crystal display device hasprojecting portions formed under the reflective electrode and extendingin all directions. The projecting portions are designed to have apattern optimal in terms of paths of an incident light and a reflectedlight. FIG. 3 illustrates a layout of projecting portions employed inthe conventional liquid crystal display device. In a reflective liquidcrystal display device, the projecting portions 108 are formed withoutespecially taking into account the effect of boundaries between pixels.In addition, a liquid crystal display device having a transmissivedisplay section and a reflective display section therein includes suchprojecting portions only within the reflective display section.

However, it has been found a problem in that the conventionalsemi-transmissive liquid crystal display device employing one kind ofcolor filter corresponding to each pixel in order to, for example,reduce the number of process steps to be carried out to manufacture thedevice has an image quality inferior to that of a device employing twokinds of color filters therein, which has been developed before theemergence of the device employing one kind of color filter.

Furthermore, it has also been found another problem in that both areflective liquid crystal display device and a semi-transmissive liquidcrystal display device have displayed images appearing pale yellow incolor thereon.

SUMMARY OF THE INVENTION

An object of the present invention is to provide a color liquid crystalpanel capable of improving quality of images to be displayed in asemi-transmissive liquid crystal display device, a method formanufacturing the same, and further a color liquid crystal displaydevice employing the same.

A color liquid crystal panel according to the first aspect of thepresent invention comprises a thin film transistor, a reflectiveelectrode connected to the thin film transistor and a transparentelectrode in each pixel thereof. Furthermore, the color liquid crystalpanel is constructed such that a display surface of the color liquidcrystal panel allows a light emitted from a backlight to exit from thedisplay surface through the transparent electrode and another lightinputted to the display surface to exit from the display surface afterbeing reflected by the reflective electrode. Additionally, the colorliquid crystal panel is constructed such that the color liquid crystalpanel has a color filter therein so that at least one opening varying anarea thereof depending on a color to be displayed is formed in the colorfilter in a part thereof facing the reflective electrode, and colorreproduction ranges of the light exiting from the display surfacethrough the transparent electrode and the another light exiting from thedisplay surface after being reflected by the reflective electrodesubstantially coincide with each other.

It should be noted that the color liquid crystal panel of the firstaspect of the present invention is further and preferably constructed asfollows. That is, a red color filter, a green color filter and a bluecolor filter are respectively formed as the color filter and a ratio ofan area of the at least one opening formed in the color filter withrespect to an area of the color filter becomes maximum in the event thegreen color filter is selected as the color filter to calculate theratio. The color liquid crystal panel is more preferably constructed asfollows. That is, in the case where a white-colored light source isemployed as the backlight, the ratio of an area of the at least oneopening formed in the green color filter with respect to an area of thegreen color filter is made two to four times the ratio of an area of theat least one opening formed in one of the red color filter and the bluecolor filter with respect to an area of associated one of the red colorfilter and the blue color filter.

Additionally, the color liquid crystal panel of the first aspect of thepresent invention described so far is preferably constructed as follows.That is, the ratio of an area of the at least one opening formed in thecolor filter with respect to an area of the color filter in the colorfilter in a part thereof facing the reflective electrode is set at avalue of not greater than 50% and further, the at least one opening isformed shaped like a slit and a width of the slit is set at a value of 1m to 10 m.

A color liquid crystal panel constructed in accordance with the secondaspect of the present invention has a thin film transistor, a reflectiveelectrode connected to the thin film transistor and a transparentelectrode in each pixel thereof. Furthermore, the color liquid crystalpanel is constructed such that a display surface of the color liquidcrystal panel allows a light emitted from a backlight to exit from thedisplay surface through the transparent electrode and another lightinputted to the display surface to exit from the display surface afterbeing reflected by the reflective electrode. Additionally, the colorliquid crystal panel comprises a color filter and a transparent filmformed between the color filter and a transparent substrate whilevarying a volume thereof depending on a color to be displayed, in whichcolor reproduction ranges of the light exiting from the display surfacethrough the transparent electrode and the another light exiting from thedisplay surface after being reflected by the reflective electrodesubstantially coincide with each other.

A color liquid crystal panel constructed in accordance with the thirdaspect of the present invention comprises a transparent substrate, athin film transistor formed in each pixel on the transparent substrate,an insulation film formed on the transparent substrate to have aconvex-concave surface within the each pixel, a reflective electrodeformed on the insulation film and connected to the thin film transistorin the each pixel, in which the insulation film has projecting portionseach extending along a boundary between adjacent pixels and having awidth substantially equal to that of projecting portions constitutingthe convex-concave surface within the each pixel.

To solve the above-described problems, the inventors of the applicationhave energetically and repeatedly carried out experiments and studies,and finally found the following problems included in the conventionaltechnology that is disclosed such as in Japanese Patent ApplicationLaid-open No. 2000-111902. That is, in a transmissive and reflectiveliquid crystal display device having one kind of color filter formedcorresponding to a color to be displayed, respective patterns ofopenings formed in associated color filters coincide with each othereven though human visual sensitivity varies depending on a color to bedisplayed. Accordingly, this construction of color filter having suchopening therein makes the color reproduction ranges of a transmissivedisplay section and a reflective display section within a pixeldifferent from each other, thereby preventing the transmissive andreflective liquid crystal display device from offering the desirablequality of images to be displayed. Taking into account an adverse effecton the quality of images to be displayed, the present invention has beenconceived to have the following construction of liquid crystal panel.That is, as described above, an area of openings formed in a colorfilter within a reflective display section is made to vary depending ona color to be displayed or a transparent film is formed between a colorfilter and a transparent substrate while varying the volume of thetransparent film depending on a color to be displayed. This constructionof liquid crystal panel makes the color reproduction ranges of atransmissive display section and a reflective display section coincidewith each other corresponding to a color to be displayed, in otherwords, with respect to individual colors to be displayed, therebycreating color balanced viewable images corresponding to a color to bedisplayed, in other words, with respect to individual colors to bedisplayed, and further achieving high quality images.

Furthermore, the inventors found that images appearing pale yellow incolor are caused by the difference in gaps between two substrates atpositions thereof located within a pixel and between pixels. Normally ina reflective liquid crystal display device, a black matrix is not formedat the boundary between pixels to make a display bright. For thisreason, it is believed that the above-described difference in gaps makesa light travel different distances through a liquid crystal to generatephase difference of light, making images appear pale yellow in color.Therefore, the liquid crystal panel of the present invention isconstructed such that projecting portions are formed also at theboundary between pixels to reduce the difference in gaps to therebyreduce pale yellow in color and achieve high quality images.

A method for manufacturing a color liquid crystal panel according to thepresent invention is constructed as follows. First, the color liquidcrystal panel has a thin film transistor, a reflective electrodeconnected to the thin film transistor and a transparent electrode ineach pixel thereof, and is further constructed such that a displaysurface of the color liquid crystal panel allows a light emitted from abacklight to exit from the display surface through the transparentelectrode and another light inputted to the display surface to exit fromthe display surface after being reflected by the reflective electrode.Secondly, the method for manufacturing the above-described color liquidcrystal panel comprises the steps of: preparing a photomask in such amanner that at least one opening is formed in the photomask so as tovary an area of the at least one opening depending on a color to bedisplayed; and forming the pattern in a raw material film constitutingthe color filter by using the photomask to make the color filter havethe at least one opening therein varying depending on a color to bedisplayed and facing the reflective electrode.

It should be noted that it is preferable for the method formanufacturing a color liquid crystal panel to further have a step offorming a transparent film covering all color filters formedcorresponding to colors to be displayed and a step of flattening thetransparent film after a step of forming the color filter.

According to the above-described method for manufacturing a color liquidcrystal panel, the color liquid crystal panel constructed in accordancewith the first aspect of the present invention and capable of displayinghigh quality images can be fabricated.

Moreover, a color liquid crystal display device of the present inventioncomprises a liquid crystal panel constructed in accordance with one ofthe first, second and third aspects of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a plan view illustrating a layout of a TFT substrate includedin a conventional semi-transmissive liquid crystal display devicedisclosed in Japanese Patent Application Laid-open No. 2000-111902;

FIG. 2 is a cross sectional view of a liquid crystal panel employed inthe conventional semi-transmissive liquid crystal display device, takenalong the line A-A of FIG. 1;

FIG. 3 illustrates a layout of projecting portions employed in theconventional liquid crystal display device;

FIG. 4 is a plan view of a layout of a TFT substrate employed in aliquid crystal panel of the first embodiment constructed in accordancewith the present invention;

FIG. 5 is a cross sectional view taken along the line A-A of FIG. 4;

FIG. 6 is a cross sectional view taken along the line B-B of FIG. 4;

FIG. 7 is a cross sectional view taken along the line C-C of FIG. 4;

FIG. 8 is a graphic illustration of a spectrum of a standard light CIE“C”;

FIG. 9 is a graphic illustration of a spectrum of a light emitted from awhite-colored LED;

FIG. 10 is a CIE chromaticity diagram showing an optimal colorreproduction range to be employed in television display and defined byNTSC;

FIG. 11 is a graphic illustration of a spectrum of a light emitted fromthe first three-wavelength light source;

FIG. 12 is a graphic illustration of a spectrum of a light emitted fromthe second three-wavelength light source;

FIGS. 13A, 13B and 13C are plan views illustrating patterns of variouscolor filters within associated pixels;

FIG. 14 is a cross sectional view, taken along the line A-A of FIG. 4,of a liquid crystal panel of the second embodiment constructed inaccordance with the present invention;

FIG. 15 is a cross sectional view, taken along the line B-B of FIG. 4,of a liquid crystal panel of the second embodiment constructed inaccordance with the present invention;

FIG. 16 is a cross sectional view, taken along the line C-C of FIG. 4,of a liquid crystal panel of the second embodiment constructed inaccordance with the present invention;

FIG. 17A is a layout diagram indicating projecting portions formed undera reflective electrode in the liquid crystal panel of the thirdembodiment of the present invention and FIG. 17B is a schematic crosssectional view of the liquid crystal panel;

FIG. 18 is a schematic diagram to explain the relationship between awidth of projecting portion and a height thereof that varies dependingon the width;

FIGS. 19A and 19B are schematic diagrams showing the method formanufacturing the projecting portions through two exposure steps;

FIGS. 20A and 20B are schematic diagrams showing the method formanufacturing the projecting portions through two exposure steps andillustrate process steps subsequent to the steps of FIGS. 19A and 19B inorder;

FIG. 21 is a schematic diagram showing the method for manufacturing theprojecting portions through two exposure steps and illustrates a processstep subsequent to the steps of FIGS. 20A and 20B;

FIGS. 22A and 22B are schematic diagrams showing the method formanufacturing the projecting portions through one exposure step;

FIGS. 23A and 23B are schematic diagrams showing the method formanufacturing the projecting portions through one exposure step andillustrate process steps subsequent to the steps of FIGS. 22A and 22B inorder;

FIG. 24 is a block diagram illustrating the configuration of a portableinformation terminal constructed in accordance with the embodiment ofthe present invention; and

FIG. 25 is a block diagram illustrating the configuration of a portabletelephone constructed in accordance with the embodiment of the presentinvention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

A liquid crystal panel constructed in accordance with embodiments of thepresent invention, a method for manufacturing the same and a liquidcrystal display device employing the same will be described in detailbelow with reference to the attached drawings. FIG. 4 is a plan view ofa layout of a TFT substrate employed in a liquid crystal panelconstructed in accordance with the first embodiment of the presentinvention. FIG. 5 is a cross sectional view taken along the line A-A ofFIG. 4, FIG. 6 is a cross sectional view taken along the line B-B ofFIG. 4 and FIG. 7 is a cross sectional view taken along the line C-C ofFIG. 4.

The first embodiment also employs the following construction of liquidcrystal panel similar to that described in the conventional liquidcrystal display device. That is, the liquid crystal panel of the firstembodiment is constructed such that a red color pixel 101R, a greencolor pixel 101G and a blue color pixel 101B are disposed in this orderin a direction in which a scanning signal line extends. In each pixel, athin film transistor (TFT) 102 is formed. The thin film transistor 102consists of a gate electrode 103 a projecting from a gate line 103 asthe scanning signal line and a drain electrode 104 a projecting from adrain line 104 that extends in a direction perpendicular to the gateline. The gate line 103 and the gate electrode 103 a are formed on atransparent substrate 100 a and further, an insulation film 105 isformed on the transparent substrate 100 a covering the gate line 103 andthe gate electrode 103 a. The drain line 104 is formed on the insulationfilm 105. An amorphous silicon layer 106 is formed on the insulationfilm 105 to face the gate electrode 103 a and the drain electrode 104 ais formed extending on the amorphous silicon layer 106. Furthermore, asource electrode 107 is formed extending from the amorphous siliconlayer 106 in a direction apart from the drain electrode 104 a while apart of the source electrode is at least positioned on and inside theamorphous silicon layer.

Furthermore, in the embodiment, each pixel is partitioned into, forinstance, nearly two equal sections, i.e., a reflective display sectionR and a transmissive display section T, by a line extending in parallelwith the scanning signal line. In this case, the reflective displaysection R is disposed in a pixel in a section thereof including the thinfilm transistor 102.

Moreover, within the reflective display section R of each pixel,projecting portions 8 are formed on the insulation film 105. Theprojecting portions 8 consist of, for example, an insulation film. Inaddition, an insulation film 10 is formed covering the projectingportions 8, the thin film transistor 102 and the like and further, acontact hole 11 is formed in the insulation film 10 so as to reach thesurface of the source electrode 107. Furthermore, in the reflectivedisplay section R, a reflective electrode 12 is formed within thecontact hole 11 and on the insulation film 10. The reflective electrode12 has a convex-concave surface reflecting the profile of the projectingportions 8. On the other hand, within the transmissive display sectionT, a transparent electrode 9 is formed on the insulation film 10 and thereflective electrode 12 and the transparent electrode 9 overlap eachother around the boundary between the reflective display section R andthe transmissive display section T. Additionally, a retardation film 113and a polarizer 114 are formed on the transparent substrate 100 a on aside thereof defined as the surface on which elements such as the thinfilm transistor 102 are not formed. The elements constructed asdescribed above constitute a TFT substrate.

Moreover, another transparent substrate 100 b is disposed in parallelwith the transparent substrate 100 a on a side thereof defined as thesurface on which the thin film transistor 102 is formed. A color filter(CF) 21 is formed on a surface of the transparent substrate 100 b on aside thereof facing the transparent substrate 100 a. As shown in FIGS. 4through 7, the color filter 21 is formed extending in parallel with thedrain line 104 and further, when viewing a pixel in a directionperpendicular to a surface of the associated transparent substrate, thetransparent electrode 9 and the reflective electrode 12 are formedinside with respect to both end lines of the color filter 21. Inaddition, within the reflective display section R, slits 21 a are formedin the color filter 21. The slits 21 a are formed to have a width of,for instance, 1 m to 10 m and further, to occupy, for instance, below50% of an area of the color filter 21 within the reflective displaysection R. Note that the ratio of an area occupied by the slits 21 awith respect to an area of the color filter 21 within the reflectivedisplay section R varies depending on a color to be displayed and in theembodiment, the ratio of an area occupied by the slits 21 a that areformed in the green color pixel 101G is made, for example, three timesthe respective ratio of an area occupied by the slits 21 a that areformed in the red color pixel 101R and the blue color pixel 101B. Notethat although the embodiment is constructed such that the slits 21 a areformed extending in a direction in parallel with the color filter 21,the embodiment is not limited to the above-described construction ofslits and therefore, may be constructed by employing another slits thathave patterns different from that of the slits 21 a.

Furthermore, an overcoat layer 25 is formed on the transparent substrate100 b filling the slits 21 a while covering the color filter 21 and anopposing electrode 122 is formed on the overcoat layer 25. The overcoatlayer 25 consists of, for example, a transparent resin and the opposingelectrode 122 consists of, for example, an ITO (Indium Tin Oxide). Aretardation film 123 and a polarizer 124 are formed on a surface of thetransparent substrate 100 b on a side thereof defined as the surface onwhich elements such as the color filter 21 are not formed. The elementsconstructed as described above constitute a CF substrate.

Subsequently, a liquid crystal 130 is interposed between the TFTsubstrate and the CF substrate.

In the first embodiment constructed as described above, in thetransmissive display section T, a light emitted from a backlight (notshown) exits to the outside through the color filter 21. In thereflective display section R, a part of a light reaching the reflectiveelectrode 12 through the color filter 21 exits to the outside throughthe slits 21 a and a part of a light reaching the reflective electrode12 through the slits 21 a exits to the outside through the color filter21. Also, the following phenomenon can be seen in the reflective displaysection R. That is, a light reaching the reflective electrode 12 throughthe color filter 21 exits to the outside through the color filter 21 anda light reaching the reflective electrode 12 through the slits 21 aexits to the outside through the slits 21 a. Therefore, a mean filmthickness of a color filter through which lights exiting from thereflective display section R transmit during the time in which thelights travel the associated distance after they are inputted to theinside until they are outputted to the outside becomes nearly equal tothat could be observed in the transmissive region T. In addition, as theembodiment employs the ratio of an area of the slits 21 a with respectto an area of the color filter within the reflective display section R(hereinafter, the ratio is referred to as “aperture ratio”) varyingdepending on a color to be displayed, it is possible to make the colorreproduction ranges of the reflective display section R and thetransmissive display section T coincide with each other with respect toa color to be displayed. As a result, the color liquid crystal displaypanel constructed as described above can display high quality images.

Subsequently, the relationship between an aperture ratio and a colorbalance will be explained below.

The inventors of this application carried out a simulation in thefollowing manner to make the above-described relationship clearer:first, decide to use a white-colored light emitting diode (LED) as abacklight; secondly, vary the film thickness of color filter; thirdly,with respect to various film thicknesses of color filter, calculate theaperture ratio so as to take the value for allowing chromaticitycoordinates of the transmissive display section to substantially matchto the CIE (Center for International Education) chromaticity coordinatesof a white display. In this case, a standard light CIE “C” was used as alight incident on the reflective display section. FIG. 8 is a graphicillustration of a spectrum of the standard light CIE “C” and FIG. 9 is agraphic illustration of a spectrum of a light emitted from awhite-colored LED. Note that an intensity of light along thelongitudinal axis shown in FIGS. 8 and 9 is normalized such that themaximum intensity of light takes the value of one. The results obtainedby carrying out the above-mentioned simulation will be illustrated inthe following Tables 1 through 7. TABLE 1 Film thickness 0.8 m x yAperture coordinate coordinate NTSC Hue ratio value value ratioTransmissive Red — 0.417 0.328 display Green — 0.329 0.377 section Blue— 0.229 0.288 White — 0.321 0.366 0.040 Reflective Red 0.20 0.417 0.319display Green 0.38 0.319 0.378 section Blue 0.27 0.239 0.288 (havingWhite — 0.318 0.334 0.042 optimal slits) Reflective Red 0 0.487 0.306display Green 0 0.316 0.417 section Blue 0 0.171 0.247 (having no White— 0.311 0.336 0.142 slits)

TABLE 2 Film thickness 1.0 m x y Aperture coordinate coordinate NTSC Hueratio value value ratio Transmissive Red — 0.430 0.328 — display Green —0.328 0.385 — section Blue — 0.217 0.279 — White — 0.321 0.337 0.054Reflective Red 0.18 0.430 0.320 — display Green 0.37 0.318 0.385 —section Blue 0.24 0.231 0.280 — (having White — 0.318 0.335 0.055optimal slits) Reflective Red 0 0.508 0.308 — display Green 0 0.3140.435 — section Blue 0 0.161 0.236 — (having no White — 0.311 0.3410.183 slits)

TABLE 3 Film thickness 1.2 m x y Aperture coordinate coordinate NTSC Hueratio value value ratio Transmissive Red — 0.443 0.328 — display Green —0.328 0.393 — section Blue — 0.206 0.271 — White — 0.320 0.338 0.069Reflective Red 0.17 0.440 0.322 — display Green 0.36 0.317 0.392 —section Blue 0.20 0.219 0.271 — (having White — 0.317 0.336 0.069optimal slits) Reflective Red 0 0.527 0.310 — display Green 0 0.3110.451 — section Blue 0 0.153 0.227 — (having no White — 0.311 0.3450.224 slits)

TABLE 4 Film thickness 1.4 m x y Aperture coordinate coordinate NTSC Hueratio value value ratio Transmissive Red — 0.455 0.328 — display Green —0.327 0.401 — section Blue — 0.196 0.263 — White — 0.319 0.338 0.086Reflective Red 0.15 0.454 0.323 — display Green 0.35 0.316 0.398 —section Blue 0.15 0.204 0.258 — (having White — 0.316 0.336 0.088optimal slits) Reflective Red 0 0.544 0.313 — display Green 0 0.3090.467 — section Blue 0 0.147 0.219 — (having no White — 0.311 0.3480.264 slits)

TABLE 5 Film thickness 1.6 m x y Aperture coordinate coordinate NTSC Hueratio value value ratio Transmissive Red — 0.473 0.329 — display Green —0.327 0.408 — section Blue — 0.185 0.252 — White — 0.319 0.339 0.108Reflective Red 0.12 0.476 0.324 — display Green 0.31 0.314 0.409 —section Blue 0.14 0.200 0.251 — (having White — 0.317 0.339 0.111optimal slits) Reflective Red 0 0.566 0.316 — display Green 0 0.3060.482 — section Blue 0 0.141 0.209 — (having no White — 0.312 0.3530.310 slits) Reflective Red 0.20 0.440 0.327 — display Green 0.20 0.3120.429 — section Blue 0.20 0.218 0.264 — (having White — 0.316 0.3460.097 constant aperture ratio regardless of a color to be displayed)

TABLE 6 Film thickness 1.8 m x y Aperture coordinate coordinate NTSC Hueratio value value ratio Transmissive Red — 0.490 0.330 — display Green —0.326 0.416 — section Blue — 0.175 0.243 — White — 0.319 0.340 0.131Reflective Red 0.11 0.488 0.327 — display Green 0.30 0.313 0.414 —section Blue 0.11 0.189 0.240 — (having White — 0.317 0.340 0.130optimal slits) Reflective Red 0 0.584 0.320 — display Green 0 0.3040.496 — section Blue 0 0.136 0.201 — (having no White — 0.312 0.3560.354 slits)

TABLE 7 Film thickness 2.0 m x y Aperture coordinate coordinate NTSC Hueratio value value ratio Transmissive Red — 0.506 0.331 — display Green —0.325 0.423 — section Blue — 0.167 0.234 — White — 0.319 0.341 0.154Reflective Red 0.09 0.506 0.328 — display Green 0.28 0.312 0.421 —section Blue 0.10 0.186 0.234 — (having White — 0.318 0.343 0.152optimal slits) Reflective Red 0 0.599 0.323 — display Green 0 0.3010.508 — section Blue 0 0.133 0.194 — (having no White — 0.313 0.3600.394 slits)

It should be noted that the NTSC ratio is a ratio of an area of a colorreproduction range of the associated display section with respect to anarea of a color reproduction range most suitable for television displayand defined by NTSC (National Television System Committee) FIG. 10 is aCIE chromaticity diagram showing a color reproduction range mostsuitable for television display and defined by NTSC.

As shown in the above-described Tables 1 through 7, in a case whereslits are formed in the color filter to make the color filter have theappropriate aperture ratio, the chromaticity coordinates and NTSC ratiocalculated with respect to the transmissive display sectionsubstantially match to those calculated with respect to the reflectivedisplay section. On the other hand, in a case where slits are not formedin the color filter within the reflective display section, thechromaticity coordinates and NTSC ratio calculated with respect to thetransmissive display section are extensively different from thosecalculated with respect to the reflective display section. Furthermore,also in a case where slits are formed in the color filter to make thecolor filter have the same aperture ratio within the reflective displaysection regardless of a color to be displayed, as shown in Table 5,difference in the color reproduction ranges of respective displaysections is not large. However, as the saturations of color observed ina green color pixel increase whereas the saturations of color observedin a red color pixel and a blue color pixel decrease, difference inrespective hues observed in the transmissive display section and thereflective display section results.

Furthermore, the inventors of this application carried out a simulationin the following manner: first, decide to use a three-wavelength lightsource (the first three-wavelength light source) as a backlight;secondly, vary the film thickness of color filter; thirdly, with respectto various film thicknesses of color filter, calculate the apertureratio so as to take the value for allowing chromaticity coordinates ofthe transmissive display section to substantially match to the CIE(Center for International Education) chromaticity coordinates. In thiscase, a standard light CIE “C” was used as a light incident on thereflective display section. FIG. 11 is a graphic illustration of aspectrum of the light emitted from the first three-wavelength lightsource. Note that an intensity of light along the longitudinal axisshown in FIG. 11 is normalized such that the maximum intensity of lighttakes the value of one. The results obtained by carrying out theabove-mentioned simulation will be illustrated in the following Tables 8through 10. TABLE 8 Film thickness 1.2 m x y Aperture coordinatecoordinate NTSC Hue ratio value value ratio Transmissive Red — 0.4470.291 — display Green — 0.335 0.387 — section Blue — 0.216 0.252 — White— 0.329 0.317 0.084 Reflective Red 0.15 0.448 0.321 — display Green 0.400.317 0.387 — section Blue 0.10 0.191 0.252 — (having White — 0.3130.331 0.082 optimal slits)

TABLE 9 Film thickness 1.6 m x y Aperture coordinate coordinate NTSC Hueratio value value ratio Transmissive Red — 0.476 0.292 — display Green —0.333 0.407 — section Blue — 0.197 0.234 — White — 0.330 0.320 0.128Reflective Red 0.12 0.476 0.324 — display Green 0.31 0.314 0.409 —section Blue 0.08 0.178 0.236 — (having White — 0.314 0.337 0.124optimal slits) Reflective Red 0.15 0.461 0.326 — display Green 0.150.311 0.440 — section Blue 0.15 0.204 0.254 — (having White — 0.3150.347 0.127 constant aperture ratio regardless of a color to bedisplayed)

TABLE 10 Film thickness 2.0 m x y Aperture coordinate coordinate NTSCHue ratio value value ratio Transmissive Red — 0.507 0.296 — displayGreen — 0.332 0.426 — section Blue — 0.182 0.214 — White — 0.331 0.3240.179 Reflective Red 0.08 0.514 0.328 — display Green 0.26 0.311 0.425 —section Blue 0.05 0.162 0.216 — (having White — 0.315 0.342 0.18 optimalslits)

As shown in the above-indicated Tables 8 through 10, in a case whereslits are formed in the color filter to make the color filter have anappropriate aperture ratio, the chromaticity coordinates and NTSC ratiocalculated with respect to the transmissive display sectionsubstantially match to those calculated with respect to the reflectivedisplay section even when the light source used in the simulationchanges. On the other hand, in a case where slits are formed in thecolor filter to make the color filter have the same aperture ratioregardless of a color to be displayed, as shown in Table 9, differencein the color reproduction ranges of respective display sections is notlarge. However, as the saturations of color observed in a green colorpixel increase whereas the saturations of color observed in a red colorpixel and a blue color pixel decrease, difference in respective huesobserved in the transmissive display section and the reflective displaysection results.

In the following description, relationship between an aperture ratio anda light source will be explained. When a spectrum of a light emittedfrom the light source varies, the chromaticity coordinates of a lightexiting to the outside through a color filter within a transmissivedisplay section vary correspondingly. This explanation will also beunderstood by comparing the figures of associated items indicated in theabove-described Tables 1 through 7 with the figures of associated itemsindicated in the above-described Tables 8 through 10. To make therelationship between an optimal aperture ratio and a light sourceclearer, the inventors carried out a simulation. In the simulation, thefilm thickness of a color filter is fixed to be 1.6 m and theaforementioned white-colored LED, the first three-wavelength lightsource and an additional three-wavelength light source (the secondthree-wavelength light source) are employed as a light source. FIG. 12is a graphic illustration of a spectrum of a light emitted from thesecond three-wavelength light source. Note that an intensity of lightalong the longitudinal axis shown in FIG. 12 is normalized such that themaximum intensity of light takes the value of one. The results obtainedby carrying out the above-mentioned simulation will be illustrated inthe following Tables 11 through 13 in which the white-colored LED, thefirst three-wavelength light source and the second three-wavelengthlight source are employed, respectively. TABLE 11 x y Aperturecoordinate coordinate NTSC Hue ratio value value ratio Transmissive Red— 0.473 0.329 — display section Green — 0.327 0.408 — Blue — 0.185 0.252— White — 0.319 0.339 0.108 Reflective Red 0.12 0.476 0.324 — displaysection Green 0.31 0.314 0.409 — (having optimal Blue 0.14 0.200 0.251 —slits) White — 0.317 0.339 0.111

TABLE 12 x y Aperture coordinate coordinate NTSC Hue ratio value valueratio Transmissive Red — 0.476 0.292 — display section Green — 0.3330.407 — Blue — 0.197 0.234 — White — 0.330 0.320 0.128 Reflective Red0.12 0.476 0.324 — display section Green 0.31 0.314 0.409 — (havingoptimal Blue 0.08 0.178 0.236 — slits) White — 0.314 0.337 0.124

TABLE 13 x y Aperture coordinate coordinate NTSC Hue ratio value valueratio Transmissive Red — 0.437 0.286 — display section Green — 0.3110.428 — Blue — 0.195 0.243 — White — 0.303 0.331 0.126 Reflective Red0.20 0.440 0.327 — display section Green 0.20 0.312 0.429 — (havingoptimal Blue 0.10 0.186 0.241 — slits) White — 0.311 0.343 0.116

As shown in Table 13, in the case where the second three-wavelengthlight source is employed in the simulation, an optimal colorreproduction range is obtained when 10 aperture ratios applied to a redcolor filter and a green color filter coincide with each other.

The results obtained by those simulations tell that regardless of alight source to be employed in the simulation, it is desirable to makethe aperture ratio applied to the green color filter largest among threeaperture ratios applied to the red, green and blue color filters.Specifically, in the case where a white-colored light source is employedin the simulation, it is preferable that the aperture ratio applied tothe green color filter is made two to four times those applied to thered and blue color filters.

It should be noted that it is preferable that the slits of the colorfilter are formed to have a width of 1 m to 10 m. When the slits areformed to have a width narrower than 1 m, operation for formingassociated patterns in the color filter becomes difficult. On the otherhand, when the slits are formed to have a width wider than 10 m,operation for flattening an overcoat layer formed on the color filterbecomes difficult.

As already mentioned in the above-described explanation, the openings ofthe color filter is not limited to the above-described slits andtherefore, may be constructed by employing another openings that havepatterns different from those of the slits. Furthermore, a positionalrelationship relatively observed between the reflective display sectionand the transmissive display section is not limited to theabove-described construction of reflective display and transmissivedisplay sections. FIGS. 13A, 13B and 13C are plan views illustratingpatterns of various color filters and positional relationship betweenreflective display and transmissive display sections within a pixel.

For instance, as shown in FIG. 13A, in the case where the reflectivedisplay section R and the transmissive display section T are partitionedin the same manner shown in the above-described embodiment, the liquidcrystal panel of the present invention may employ an opening 41 a thatis formed in the color filter 41 so as to be positioned in the center ofthe reflective display section R.

In addition, as shown in FIG. 13B, also in a case where the reflectivedisplay section R and the transmissive display section T are partitionedsuch that the reflective display section R is surrounded by thetransmissive display section T, the liquid crystal panel of the presentinvention may employ an opening 42 a that is formed in a color filter 42so as to be positioned in the center of the reflective display sectionR.

Moreover, as shown in FIG. 13C, in a case where the reflective displaysection R and the transmissive display section T are partitioned suchthat the transmissive display section T is interposed between the tworeflective display sections R, the liquid crystal panel of the presentinvention may employ the following construction of pixel. That is, thepixel is constructed such that a color filter 43 is formed to have itsend lines 43 a positioned nearer the transmissive display section T thanthe outer end lines of the two reflective display sections R, therebycreating regions in the pixel in which the color filter 43 is notformed.

It should be noted that regardless of a pattern of color filter, it ispreferable that the ratio of an area of openings with respect to that ofthe reflective display section is made equal to or less than 50%. Inother words, it would be desirable to form the color filter so as tooccupy at least 50% of an entire area of the reflective display section.The reason is as follows. That is, when the color filter is formed tooccupy less than 50% of an entire area of the reflective displaysection, the ratio of lights that have no opportunities to transmitthrough the color filter during the time in which the lights travel theassociated distance after they are inputted to the inside until they areoutputted to the outside with respect to entire lights associated withthe reflective display section increases, thereby making it difficultfor the color reproduction range of the reflective display section tocoincide with that of the transmissive display section.

The second embodiment of the present invention will be described below.In the second embodiment, the film thickness of color filter within areflective display section is made thinner than that within atransmissive display section. FIGS. 14, 15 and 16 are cross sectionalviews, each illustrating a structure of a liquid crystal panel of thesecond embodiment constructed in accordance with the present invention,taken along the line A—A of FIG. 4, the line B—B of FIG. 4 and the lineC—C of FIG. 4, respectively. Note that the parts and components used inthe second embodiment shown in FIGS. 14, 15, 16 and also used in thefirst embodiment shown in FIGS. 4, 5, 6, 7, 8 are denoted by the samenumerals as those referred in the first embodiment, thereby omittingdetailed explanation thereof.

The second embodiment also includes the following construction of liquidcrystal panel similar to that described in the first embodiment. Thatis, the liquid crystal panel of the second embodiment is constructedsuch that each pixel is partitioned into, for example, nearly two equalsections, i.e., a reflective display section R and a transmissivedisplay section T, by a line extending in parallel with the scanningsignal line. Furthermore, a TFT substrate is constructed in the samemanner as that employed in the first embodiment.

A CF substrate of the second embodiment is constructed such that a colorfilter 51 is formed on a surface of a transparent substrate 100 b on aside thereof facing a transparent substrate 100 a. In addition, withinthe reflective display section R, a transparent resin layer 52 is formedbetween the color filter 51 and the transparent substrate 100 b. In thiscase, the ratio of a volume of the transparent resin layer 52 withrespect to an entire volume of the color filter 51 and the transparentresin layer 52 within the reflective display section R (hereinafter, theratio is referred to as “volume ratio”) is set at a value of, forexample, 35% to 65%. The volume ratio can be adjusted by varying a filmthickness or an area of the transparent resin layer 52. Note that thevolume ratio varies depending on a color to be displayed and in theembodiment, the volume ratio applied to a green color pixel 101G ismade, for example, about three times the volume ratio applied to a redcolor pixel 101R and a blue color pixel 101B. Furthermore, although theembodiment is constructed such that the transparent resin layer 52 isformed completely overlapping the color filter 51, the embodiment is notlimited to the above-described construction of transparent resin layerand color filter. Additionally, it would be desirable that the colorfilter 51 has a flat surface in the same plane over two areas thereofcorresponding to the reflective display section R and the transmissivedisplay section T.

In the liquid crystal panel of the second embodiment constructed asdescribed above, within the transmissive display section T, a lightemitted from a backlight (not shown) exits to the outside through thecolor filter 51. Within the reflective display section R, a lightreaching the reflective electrode 12 through the color filter 51 exitsto the outside through the color filter 51. In this case, as the filmthickness of the color filter 51 within the reflective display section Ris being made approximately half that of the color filter 51 within thetransmissive display section T, the substantial film thickness of colorfilter through which lights transmit during the time in which the lightstravel the associated distance after they are inputted to the insideuntil they are outputted to the outside becomes nearly equal to thatcould be observed within the transmissive display section T.Furthermore, in the embodiment, as the volume ratio calculated withrespect to the volume of the transparent resin layer 52 is made to varydepending on a color to be displayed, it becomes possible for the colorreproduction range of the reflective display section R to coincide withthat of the transmissive display section T, thereby allowing the liquidcrystal panel to display high quality images.

Subsequently, the relationship between a volume ratio and a colorbalance will be explained below. The inventors of this applicationcarried out the simulation similar to that performed in the firstembodiment to make the above-described relationship clearer: first,decide to use a white-colored LED as a backlight; secondly, vary thefilm thickness of color filter and at the same time, vary the area oftransparent resin layer; thirdly, with respect to various filmthicknesses of color filter, calculate the volume ratio so as to takethe value for allowing chromaticity coordinates of the transmissivedisplay section to substantially match to the CIE (Center forInternational Education) chromaticity coordinates. In this case, astandard light CIE “C” is used as a light incident on the reflectivedisplay section. The results obtained through the above-describedsimulation will be indicated in the following Tables 14 and 15. TABLE 14Film thickness 2.2 m x y Area Volume coordinate coordinate NTSC Hueratio ratio value value ratio Transmissive Red — — 0.518 0.333 displayGreen — — 0.325 0.43 section Blue — — 0.161 0.227 White — — 0.319 0.3420.175 Reflective Red 0.82 0.58 0.51 0.309 display Green 0.98 0.41 0.3140.427 section Blue 0.70 0.48 0.158 0.23 (having White — — 0.313 0.340.18 optimal transparent resin layer)

TABLE 15 Film thickness 2.0 m x y Area Volume coordinate coordinate NTSCHue ratio ratio value value ratio Transmissive Red — — 0.506 0.331display Green — — 0.325 0.423 section Blue — — 0.167 0.234 White — —0.319 0.341 0.154 Reflective Red 0.80 0.60 0.501 0.308 display Green1.00 0.42 0.316 0.417 section Blue 0.70 0.48 0.163 0.235 (having White —— 0.313 0.337 0.158 optimal transparent resin layer)

It should be noted that “area ratio” indicated in the tables representsthe ratio of an area of transparent resin layer with respect to an areaof color filter within the reflective display section and “volume ratio”represents the ratio of a volume of transparent resin layer with respectto an entire volume of color filter and transparent resin layer withinthe reflective display section. In addition, “film thickness” representsa film thickness of color filter within the transmissive displaysection, coinciding with an entire film thickness of color filter andtransparent resin layer within the reflective display section.

As indicated in the above-described Tables 14 and 15, in a case where atransparent resin layer is formed within the reflective display sectionto have an appropriate volume ratio, the chromaticity coordinates andNTSC ratio calculated with respect to the transmissive display sectionsubstantially match to those calculated with respect to the reflectivedisplay section.

A method for manufacturing the liquid crystal panel of the firstembodiment will be explained below. A TFT substrate can be manufacturedby using the same method as that employed to manufacture theconventional liquid crystal panel. On the other hand, a CF substrate canbe manufactured using, for instance, the following method: first, coat aphotosensitive resin film as a raw material film that constitutes amonochrome color filter on a transparent substrate 100 b; secondly,expose the photosensitive resin film using a photomask that has apredetermined slit pattern therein and then, develop the photosensitiveresin film. Through those steps, the photosensitive resin film ispatterned to constitute a monochrome color filter 21 having slits 21 atherein. Those steps are carried out to form three color filters 21respectively. Note that the ratio of an area of a pattern to be formedin the photomask corresponding to the slits with respect to an area ofthe photomask, for example, is made maximum when using a photomask toform a green color filter. That is, the ratios applied to the associatedcolor filters are individually adjusted. In other words, the photomasksare individually formed to have a pattern associated with a slit patternformed in the color filter and corresponding to a color to be displayed.In a case where a white-colored light source is employed in the liquidcrystal display device, it is preferable that the ratio of an area ofslit pattern with respect to an area of the photomask used to form agreen color filter is made about two to four times that should beapplied to a photomask to form a red or blue color filter.

After formation of three color filters, an overcoat layer is formed onan entire surface of the transparent substrate 100 b while achievingflatness thereof and further, an opposing electrode is formed thereon.Furthermore, a retardation film and a polarizer are formed on a surfaceof the transparent substrate 100 b on a side thereof defined as thesurface on which the color filter is not formed.

A method for manufacturing the liquid crystal panel of the secondembodiment will be explained below. A TFT substrate can be manufacturedby using the same method as that employed to manufacture theconventional liquid crystal panel. On the other hand, a CF substrate canbe manufactured using, for instance, the following method: first,previously prepare photomasks in such a manner that the photomasks eachare formed corresponding to a color to be displayed to have a patterntherein corresponding to a pattern of transparent resin film; secondly,coat a raw material film that constitutes a transparent resin film on atransparent substrate 100 b; thirdly, form an associated pattern in theraw material film using the above-described photomask followed byformation of a transparent resin film 52 on the transparent substrate100 b; fourthly, coat another raw material film that constitutes a colorfilter on the transparent substrate 100 b and then, carry out associatedprocess steps of, for instance, exposing and developing the another rawmaterial film to form the color filter so as to have a flat surfacethereof corresponding to a color to be displayed. Note that the ratio ofan area of a pattern formed in the photomask and corresponding to apattern of transparent resin film with respect to an area of photomask,for example, is made maximum when using the photomask to form a greencolor filter. That is, the ratios applied to the associated colorfilters are individually adjusted. In other words, the photomasks areindividually formed to have a pattern corresponding to a pattern oftransparent resin film and a color to be displayed. In a case where awhite-colored light source is employed in the liquid crystal displaydevice, it is preferable that the ratio of an area of a pattern formedin the photomask with respect to an area of photomask, which is appliedto a photomask used to form a green color filter, is made about two tofour times that should be applied to a photomask to form a red or bluecolor filter.

After formation of three color filters, an overcoat layer is formed onan entire surface of the transparent substrate 100 b while achievingflatness thereof and further, an opposing electrode is formed thereon.Furthermore, a retardation film and a polarizer are formed on thetransparent substrate 100 b on a backside thereof defined as the surfaceon which the color filter is not formed.

It should be noted that although the liquid crystal panel employed inthe first and second embodiments does not have a black matrix betweenthe adjacent color filters of the CF substrate, the liquid crystal panelmay be constructed such that the black matrix is formed between theadjacent color filters of the CF substrate. Furthermore, although theliquid crystal panel employed in the first and second embodiments have acolor filter formed on a transparent substrate on which a thin filmtransistor is not formed, the liquid crystal panel may be constructedsuch that the color filter is formed on a substrate on which a thin filmtransistor is formed. In this case, the color filter is formed on, forexample, a reflective electrode or a transparent electrode.

The third embodiment of the present invention will be described below.An object of the third embodiment is to provide a liquid crystal displaydevice in which an improvement in the chromaticness of color isperformed. FIG. 17A is a layout diagram indicating projecting portionsformed under a reflective electrode in the liquid crystal panel of thethird embodiment of the present invention and FIG. 17B is a schematiccross sectional view of the liquid crystal panel.

In the first and second embodiments, the projecting portions 8 areformed under the reflective electrode in all directions to make thereflective electrode have a convex-concave surface that reflects theprofile of the projecting portions. In the embodiment, in addition tothe projecting portions 8, projecting portions 58 formed in the samestep through which the projecting portions 8 are formed are formed inboundary regions between pixels that are located adjacent to each otherin a direction in which a scanning signal line (gate line) extends. Thewidth and height of the projecting portion 58 are substantially the sameas those of the projecting portion 8.

According to the third embodiment constructed as described above, asshown in FIG. 17B, difference between a gap “d1” between a color filter21 and an insulation film 10 under the reflective electrode within apixel and a gap “d2” between a transparent substrate 100 b and theinsulation film 10 in the boundary regions between pixels is made tobecome shorter than that observed in the conventional liquid crystalpanel. In more detail, as undesirable boundary regions in which theprojecting portions 108 are not formed exist in boundary regions betweenpixels in the conventional liquid crystal panel, a gap between theundesirable boundary regions and the transparent substrate 100 b becomesextremely long in comparison with the gap observed in the embodiment inwhich such undesirable boundary regions never exist. According to theliquid crystal panel of the embodiment, images appearing pale yellow incolor are substantially eliminated from a display thereof.

It should be noted that assuming a width of the projecting portion 58 isdesigned to be W1 and a width of the projecting portion 8 is designed tobe W2, it is preferable that the projecting portions 58 and 8 are formedsatisfying the following equation:(W2−1).W1.(W2+1) (unit:m)Furthermore, it is more preferable that the projecting portions 58, 8are formed satisfying the following equation:(W2−0.5).W1.(W2+0.5) (unit:.m)FIG. 18 is a schematic diagram to explain the relationship between awidth of projecting portion and a height thereof that varies dependingon the width. In a case where “W2” is made longer than “W1”, when theprojecting portions are subjected to heat treatment (liquefaction of amaterial through baking) in an associated manufacturing step, differencebetween surface tensions of the projecting portions 8 and 58 makes thematerial constituting the projecting portion 8 flow, as indicated by thearrow “A,” into the projecting portion 58. As a result, the height ofthe projecting portion 58 becomes longer than the designed value whereasthe height of the projecting portion 8 becomes shorter than the designedvalue. On the contrary, in a case where “W2” is made shorter than “W1”,the height of the projecting portion 58 becomes shorter than thedesigned value whereas the height of the projecting portion 8 becomeslonger than the designed value, thereby making it impossible toeliminate the difference between the gaps “d1” and “d2.” Accordingly, itis desirable to design the values of “W1”and “W2” to becomesubstantially equal to each other while securing the above-describedmargin in the equations. Note that if the cross sectional view shown inFIG. 17B is accurately drawn so as to correspond to FIG. 17A, theprojecting portion 8 should also be drawn in FIG. 17B. However, forsimplicity, in the cross sectional view shown in FIG. 17B, theprojecting portions 8 are omitted whereas the projecting portions 58 aredrawn. Furthermore, it should be understood by those skilled in the artthat the liquid crystal panel shown in FIG. 14 and FIG. 16 is alsoconstructed as described above, that is, constructed such that theprojecting portions 58 having the same width and height as those of theprojecting portions 8 are being formed in addition to the projectingportions 8.

A method for manufacturing projecting portions under a reflectiveelectrode using a single photosensitive resin film will be explainedbelow. First, a method for manufacturing the projecting portions throughtwo exposure steps will be explained and then, a method formanufacturing the same through one exposure step will be explained.FIGS. 19A, 19B, 20A, 20B and 21 are schematic diagrams showing themethod for manufacturing the projecting portions through two exposuresteps in order.

First, as shown in FIG. 19A, after formation of a TFT (not shown) andthe like, coat a resist film 71 consisting of a photosensitive resin ona transparent substrate 100 a. Until the above-described coating iscompleted, prepare a photomask 72 in such a manner that a Cr film 73that prevent a light from being incident on the resist film 71 on a partthereof corresponding to the projecting portions is formed on atransparent substrate 74.

Subsequently, as shown in FIG. 19B, expose the resist film 71 consistingof a photosensitive resin using the photomask 72 to form exposedportions 71 a in the resist film 71. In this case, the depth of exposureis preferably limited to the position located, for example, about halfthe film thickness of the resist film 71 consisting of a photosensitiveresin down from the surface of the resist film.

Thereafter, as shown in FIG. 20A, prepare a photomask 75 in such amanner that a Cr film 76 having an opening only in a part thereofcorresponding to a contact hole 11 is formed on a transparent substrate74. Then, expose the resist film 71 consisting of a photosensitive resinusing the photomask 75 to form another exposed portion 71 a in theresist film 71, which corresponds to the portion of the resist filmwhere the contact hole 11 will be formed later on, so as to reach thesurface of a source electrode (not shown).

After that, as shown in FIG. 20B, develop the resist film to remove theexposed portions 71 a.

Subsequently, as shown in FIG. 21, bake the resist film 71 consisting ofa photosensitive resin to flow to round the steps existing at thesurface of the resist film 71 consisting of a photosensitive resin. As aresult, the projecting portions and the contact hole 11 are formed.

A method for manufacturing the projecting portions through one exposurestep will be explained below. FIGS. 22A, 22B, 23A and 23B are schematicdiagrams showing the method for manufacturing the projecting portionsthrough one exposure step in order.

First, as shown in FIG. 22A, after formation of a TFT (not shown), coata resist film 71 consisting of a photosensitive resin on a transparentsubstrate 100 a. Until the above-described coating is completed, preparea photomask 82 in the following manner. That is, a semi-transparent film83 having an opening only in a part thereof corresponding to a contacthole 11 is formed on a transparent substrate 84 and further, a Cr film85 that prevents a light from being incident on the resist film 71 on apart thereof corresponding to the projecting portions is formed on thesemi-transparent film. In this case, the semi-transparent film 83consists of, for instance, a metal oxide film.

Subsequently, as shown in FIG. 22B, expose the resist film 71 consistingof a photosensitive resin using the photomask 82 to form exposedportions 71 b. In this case, the depth of exposure through thesemi-transparent film 83 is preferably limited to the position located,for example, about half the film thickness of the resist film 71consisting of a photosensitive resin down from the surface of the resistfilm. As a result, the exposed portion 71 b is formed in the resist film71 consisting of a photosensitive resin. A portion, corresponding to thecontact hole 11, out of the exposed portion 71 b, directly receives anexposure light that does not transmit through the semi-transparent film83 and therefore, the depth of exposure is positioned in proximity tothe surface of a source electrode (not shown).

Thereafter, as shown in FIG. 23A, develop the resist film to remove theexposed portions 71 b.

Subsequently, as shown in FIG. 23B, bake the resist film 71 consistingof a photosensitive resin to flow to round the steps existing at thesurface of the resist film 71 consisting of a photosensitive resin. As aresult, the projecting portions and the contact hole 11 are formed.

It should be noted that although the embodiment employs a resist filmconsisting of a photosensitive resin to form projecting portions,instead of it, the embodiment may employ the following method formanufacturing projecting portions. That is, for example, form aplurality of projecting portions consisting of an insulation film andfurther, form another insulation film thereon covering an entire surfaceof the insulation film, thereby forming a convex-concave surface withinpixels and in a boundary between pixels.

Furthermore, the liquid crystal panel of the present invention may beconstructed by combining one of the constructions of liquid crystalpanel employed in the first and second embodiments with the constructionof liquid crystal panel employed in the third embodiment.

The liquid crystal panel constructed in accordance with thoseembodiments can be applied to, for example, a monitor of a portableinformation terminal, a portable telephone, a portable personalcomputer, a notebook-size personal computer or a disk-top personalcomputer. FIG. 24 is a block diagram illustrating the configuration of aportable information terminal constructed in accordance with theembodiment of the present invention. In addition, FIG. 25 is a blockdiagram illustrating the configuration of a portable telephoneconstructed in accordance with an embodiment of the present invention.

A portable information terminal 250 constructed in accordance with theembodiment of the present invention includes a display unit 268comprised of a liquid crystal panel 265, a backlight unit 266 and animage signal processing unit 267 for processing an image signal.Furthermore, the portable information terminal 250 includes a controlunit 269 for controlling components that constitute the portableinformation terminal 250, a storage unit 271 for storing programsexecuted by the control unit 269 and various data, a communication unit272 for transmitting data to and receiving data from external devices,an input unit 273 comprised such as of a keyboard or a pointer and apower supply unit 274 for supplying power to the components thatconstitute the portable information terminal 250. Note that the first,second and third embodiments described above are applied to the liquidcrystal panel 265.

The portable information terminal 250 thus constructed in accordancewith the embodiment is able to display high quality images by creatingcolor balanced viewable images or suppressing pale yellow in color.

A portable telephone 275 constructed in accordance with the embodimentof the present invention includes a display unit 276 comprised of aliquid crystal panel 265, a backlight unit 266 and an image signalprocessing unit 267 for processing an image signal. Furthermore, theportable telephone 275 includes a control unit 277 for controllingcomponents that constitute the portable telephone 275, a storage unit278 for storing programs executed by the control unit 277 and variousdata, a transmission unit 281 for transmitting a radio signal toexternal devices, an input unit 282 comprised such as of a keyboard or apointer and a power supply unit 283 for supplying power to thecomponents that constitute the portable telephone 275. Note that thefirst, second and third embodiments described above are applied to theliquid crystal panel 265.

The portable telephone 275 thus constructed in accordance with theembodiments also is able to display high quality images by creatingcolor balanced viewable images or suppressing pale yellow in color.

As described so far, according to the present invention of claims 1 to10, as an opening occupying an area varying depending on a color to bedisplayed is formed in a color filter whereas only one kind of colorfilter is formed corresponding to each pixel, it is possible for aliquid crystal panel of the present invention to make color reproductionranges of a reflective display section and a transparent display sectionsubstantially coincide with each other within each pixel. Thisconstruction of liquid crystal panel makes it possible for a liquidcrystal panel to achieve high quality images without increase in processsteps for manufacturing a liquid crystal panel. Specifically, in thecase where an aperture ratio applied to a color filter that is used todisplay a green color of high visibility is made maximum, difference incolor reproduction ranges of a reflective display section and atransparent display section can further be reduced. Furthermore,according to the present invention of claim 11, as variation in a gapbetween substrates interposing a liquid crystal therebetween is reduced,pale yellow in color observed in the conventional liquid crystal panelcan be reduced.

In addition, according to the method of the present invention of claims12 and 13, a color liquid crystal panel having such advantages in theconstruction of color filter can be manufactured.

Moreover, according to the present invention of claims 14 to 16, a colorliquid crystal panel having advantageous constructions of color liquidcrystal panel described so far can be applied to a color liquid crystaldisplay device.

1. A color liquid crystal panel comprising: a display surface withplural pixels, each of said plural pixels comprising, a thin filmtransistor, a reflective electrode connected to said thin filmelectrode, a transparent electrode, and plural color filters that eachhas a different color and a first part facing said reflective electrodeand a second part facing said transparent electrode, wherein said firstpart has at least one opening whose area depends on the color; and saidpanel further comprising a backlight that is arranged so that light fromsaid backlight exits said display surface after passing through saidtransparent electrode and said second part, wherein external light inputinto said display surface and through said first part and said at leastone opening is reflected by said reflective electrode and exits saiddisplay surface after again passing through said first part and said atleast one opening.
 2. The panel of claim 1, wherein said first andsecond parts and said at least one opening have sizes so that colorreproduction ranges of (a) the light that exits said display surfaceafter passing through said transparent electrode and (b) the externallight that exits said display surface after again passing through saidfirst part and said at least one opening, substantially coincide witheach other.
 3. The panel of claim 2, wherein said first and second partsare substantially the same size.
 4. The panel of claim 3, comprisingthree of said color filters that are red, green, and blue, and whereinsaid at least one opening in said first part of said green color filteris larger than said at least one opening in each said first part of saidred and blue color filters.
 5. The panel of claim 4, wherein said secondpart does not have an opening therein.
 6. The panel of claim 1, whereinsaid first and second parts are substantially the same size.
 7. Thepanel of claim 1, comprising three of said color filters that are red,green, and blue, and wherein said at least one opening in said firstpart of said green color filter is larger than said at least one openingin each said first part of said red and blue color filters.
 8. The panelof claim 1, wherein said second part does not have an opening therein.9. The panel of claim 1, wherein said at least one opening causes acolor reproduction range of the external light that exits said displaysurface after again passing through said first part and said at leastone opening to be narrower than if said at least one opening were notpresent in said first part.